<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <script>
      const obj = {
        // [Symbol.toPrimitive]:function() {},
        [Symbol.toPrimitive](hint) {
          // console.log("hello", hint);
          return 100;
        },
      };
      console.log(Number(obj)); // 100
      console.log(String(obj)); // 100
      console.log(obj - 100); // 100-100
      console.log(obj + {}); // 100+{}
    </script>
  </body>
</html>
